Hydrocarbon conversion



Feb. 1, 1944. G. G. LAMB ET Ai.

HYDROQARBON CONVERSION` Filed Jan. 25, 1939 reieeie'a Fes. 1, 1944 UNITED STATE mnocAnBoN-'coNvnnsloN i George G. Lamb ena rera n. Binnen, chicago,

Ill., assignors to Standard Oil Company, (ihicago, lll., a corporation of Indiana Application Jennery 2 5, 1939, serial No. 252,726 11 claims. fcl. 19e-1o) This invention relates to an improved process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons suitable for .use as motor fuel. More particularly, this invention 'relates to an improved process wherein normally gaseous hydrocarbons are converted catalytically to branched-chain hydrocarbons of high antiknock characteristics.

It has been recognizedv for some time that branched-chain parains are much more satisfactory for use as fuels in high compression automotive and airplane engines than straight-chain hydrocarbons. AMany expedients are employed to convert straight-chain hydrocarbons, particularly those found in gasoline from refinery processes, to branched-chain or isomeric hydrocarbons in order to increase the utility of these hy- `drocarbons in high compression engines. T hese expedients include such processes as reforming, catalytic cracking, catalyticisomerization, etc.

It is also known that under suitable conditions olens may be made to polymerize with other voleins or to alkylate parans thus forming hydrocarbons of higher molecular weight. If either or both of the reacting constituents is ofthe branched-chain type th'productwill also contain branched-chains.

An object of our invention is to provide an improved process vfor the conversion of normallyl gaseous hydrocarbons to hydrocarbons vof high antiknock value. Another object of our invention is to provide an-improved combination of polymerization and alkylation for converting nor- Y 'mally` gaseous hydrocarbons comprising both parafiins and oleinsV to normally liquid hydrocarbons. Further objects will become apparent,

The invention will now be described in coniunction with the accompanying drawing which is a flow diagram of one preferred embodiment of our invention.

In brief, our invention contemplates the separationV of normally gaseous paramnic and olenic hydrocarbons into fractions containing predominantly 2, 3, and 4 carbon atoms, selectively polymerizing the olens from the 4 carbon atom fraction, alkylating a portion of the isobutane from the 4 carbon atom fraction with olens from oneA of the other fractions, further alkylating the remainder of the isobutane with the olens from Athe remaining fraction and returning unreacted gases to the conversion steps for further treatment.

Referring now to the drawing: feed stock enters through line I0. This feed stock may be any mixture of normally gaseous hydrocarbons containing ethane, propane and the butanes together .with the corresponding olens as well as methane and possibly hydrogen. The off gases from the cracking of petroleum oils to produce gasoline are particularly suitable as a feed for our process especially since in the past it has been customary to regard such gases as by-products and to utilize them chiefly as fuel. The gases are compressed in compressor II and forced into absorber I2 where they are contacted with Aa suitable absorber or scrubbing oil while under pressures of 50 to -350 pounds per square inch gauge. Unabsorbed gases consisting predominantly ofl hydrogen'and methane are removed from the top of absorber I2 through line I3 and may be removed from the system. The absorbv ing medium used in 'absorber I2 will ordinarily be an yoil of the character of light gas oil but lighter p oducts may also be used, if advanta l geous. e enriched absorber oil is'withdrawn from absorber I2 through line I4 passing through heat exchanger I5 into stripping tower I6 which is provided with suitable bottom heating means Il and which may also be provided with top cooling means I8. The strippedabsorber oil is removed from stripper ilthrough line I9 and heat exchanger I 5, cooled in cooler 20 and returned to absorber. I2.

Uncondensed vapors and gases from stripper I6 are passed into fractionator 2| through line 22. AFractionator 2|, having y, bottom heating means 23 and top cooling means 24 is of the super-fractionator type effecting the separation of the gases into fractions predominating in 2, 3,

Q and 4 carbon atoms respectively. Hydrocarbons ieavier than the butanesA are withdrawn from the bottom of fractionator 2| through line 25 and may be discharged from the system through valved line 26 or returned for use as an absorber oil through line 21 which joins line I9. Other -means for separating the gaseous hydrocarbons into the desired fractions will occur readily to one skilled in the art.

The butane -fraction which contain normal and isobutanes, the normalbutenes and isobutylene iswlthdrawn through line 28, heated in heater 29 and sent to polymerizer 30 for. the conversion of the olens present.

In polymerizer 30 the polymerization of the olens in the butane cut may be accomplished by any one of a number of methods, for example the gases heated to a temperature from about 300 F.

to about 325 F. may be passed over ,a catalyst consisting of phosphoric acid on kieselguhr `at a pressure of about 650 pounds per square inch. In this event the gases will enter at the top of ypolymerizer 30 and pass down over the catalyst,

being discharged near the bottom of the reactor 30 through line-3|. Under these conditions the isobutylene is the predominate oleiln undergoing reaction although a small amount of the normal butylenes will be converted by interpolymerization with the isobutylene. If the reaction is carried out at 325 F. to 350 F. at 650 poimds per square inch pressure additional interpolymerization who normal olens and iso-olens will take place. The resulting product will be predominately iso-octene. with some trimers. g

' Another suitable catalyst comprises sulfuric acid oi' about 60 to 70% H2SO4 and preferably about 65% H2SO4 which is employed at above about '70 F. and below about 105 F. and preferably at about 85 F. and at-approximately atmospheric pressure or a little above. Under theseconditions only the isobutylene is absorbed in the sulfuric acid leaving the normal butylenes comparatively unreacted. Using this operation heat- -er 29 may be replaced by a cooler to insure the proper temperature and poiymerizer ,30 in which contact is'made by mechanical means to obtain an ulsion will be followed by separators to separate the polymer and gases from the sulfuric acid. A wash step may also be included to remove any entrained acid from the hydrocarbons.

. Sulfuric acid may also be used as a catalyst at higher temperatures in order to obtain an inter-- polymerization between the isobutylene and the normal butylenes present. Temperatures above 140 F. and preferably at about 175 F., are employed using an acid of approximately the same p concentration as in the previously. described sulfuric acid polymerization. The product again is almost entirely octenes of the branched-chain' type with some trimers present.

Another mode of converting the olens present in the "butane f eed stock is to use boron uoride as a catalyst. In order to obtain products of the gasoline boiling range it is desirable to maintain the polymerization reactor with va'bottom. temperature of about 250 to about 350 F. and preferably about 300 F.` and the top of the tower at a suitably lower temperature usually within the rangev of about 150 to about 180 F. The reactor will be maintained at sulcient pressure so that the hydrocarbons containing 6 or more carbon atoms will be liquids at the temperature existing at the bottom of the tower. This type of catalytic polymerization removes .the isobutylene almost exclusively with comparatively little eiect on the normal butylenes. l

Boron uoride may also be used as catalyst for the production of polymers of higher molecular weight from the isobutylene present in the feed stock. If the temperature of the reactor is maintained at about F. to about 40 F. and under sub-atmospheric pressure the resulting polymer will be in the nature of an oil, the viscosity of which will depend upon the particular temperature of operation, a lower temperature producing an oil of higher viscosity. If the reaction is carried out at from about 10 to about -100 F. a-heavy polymer o! resin-like tendencies and extremely high molecular weight isV formed, the lower temperatures 'again producing the heavier polymer. This polymerization reaction will remove eiectively the iso-olens from the butane iced with the production or valuable hydrocarbon u 43 the products. Since the demand for gasolines usually exceeds to a considerable extent the demand for oils and resins-we prefer to operate our polymer- A pose is the double salt type wherein aluminum chloride is one of the constituents. Specic examples include sodium chloroaluminate, lithium chloroaluminate, barium chloroaluminate, calcium chloroaluminate, etc. either as such or deposited on a suitable carrier such as pumice or kieselguhr. With catalysts of thistype the preferred range of conditions to be maintained in catalyst chamber 30 are pressures of 200 to 1000 pounds per square inch and preferably of about 500 to '150 pounds per square inch and temperatures of 250 `to 550 F. and preferably of 300 to 400 F. Again the product will be hydrocarbons of branched-chain structure within the gasoline` boiling range.

`The various. details in reference to the polymerization procedure have not been illustrated and it should be understood that polymerization re- Yactor 30 is intended to represent an integrated polymerization process having the Anecessary mixing, separating and discharge means with the accompanying cooling or heating means, etc., and means forl regeneration if it is to be used, all of which will be well known to one skilled in the art. Othercatalysts for the conversion of olens to polymers are known and can be utilized in our Pl'OeSS- Polymerized olens plus unreacted gases are led from polymerizer 3l by line 3| to fractionator 32- equipped with bottom heating means 33 and top cooling means 34. Within fractionator 32 the unreacted gases are separated from the polymer and the polymer withdrawn through -line 3i. This. polymer may be discharged from the system f through valved line 3B but since it will be .an

isomerlc octene in most-cases it is desirable to hydrogenate it to the parailin. This is accomplished by directing it through heater 31 in line V 33 together with hydrogen from line 3! which is forced into the system under high pressure by means of pump 4l. The mixed oleiinv polymer is hydrogenated in hydrogenator 4| which'niay be any suitable reactor for this purpose. One metbodof accomplishing this result is by the use `of a nickel catalyst using hydrogen pressures of about 15 pounds persquare inch absolute and a tem- -peratureof 400 F. The hydrogenated polymer .which will be^ chie1ly,isooctane (trlmethyl pentime) having anoctane number of at least 90 is discharged through line 42, or sent to blendool ing tank I I 2 through line 42a while the hydrogen is removed through line 43 and. discharged from the system through line 44 or recycled to line 39 byline45, g'

The gases from fractionator 32 now -consist chieily of normal and isobutanes together with any unreacted isobutylene and normal butylenes.

' If the polymerization reaction has been carried out to polymerize only the isooleilns then the normal oleilns will be present in considerable amount. These gases are discharged from fractionator 32- through line 46. The fraction from fractionator 2l comprising predominantly parafilns and olens having 3-carbon atoms to the molecule is added to the gases from fractionator 32 by means of line" and directed to alkylation reactor 48 throughline 49 .having heating means 5l and pump 5I.- In alkylation'reactor isobutanepres'ent from fractionator 32 is allqlated by` the propylene present in the fraction fromline 41 to yield' an alkylated product comprising predominantly branched-chain heptanes. This alkyl-ation may'be accomplished in various ways but preferably bythe use of a catalyst.

As a catalyst may be used,'for example, a salt of the double type of which one of the constituents is aluminum chloride. A preferred catalyst of this nature is sodium chloroaluminate although such salts as lithium chloroaluminate and calcium chloroaluminate may be used equally well. In this case the alkylation reactor 48 will be maintained at a temperature of approximately 400 F. and a pressure of about 500 to about 2000 pounds per square inch gauge.

Another suitable catalyst is sulfuric acid of from about 90 to about 101% HzSO4 and preferably about- 96% to 97% HzSO4. The hydrocarbon gases and sulfuric acid, are formed into an emulsion by mixing means 52.- The temperature of the emulsion is maintained -ai; from about F. to about 95 F. and preferably between 40 F. and 60 F. This may be accomplished by a cooling jacket 53 about alkylation reactor 48 or by any other suitable means, such as cooling coils, etc. drawn from alkylation reactor 48 through line 54 and allowed to separate in separator 55. The

y acid is withdrawn from separator 55 through line 56 and discharged-from thesystem for regeneration if necessary through line 51 or returned to the alkylation reactor through valved line 58 which joins line 59 through which fresh catalyst may be admitted. The hydrocarbons, consisting of alkylated isobutane and unreacted gases are withdrawn from separator 55 through line 50 and sent to fractionator 5| havingA bottom heating means 62 and top cooling means 53 by means of line 54. In order to remove traces of catalyst it may be desirable to wash the hydrocarbon stream in washer 65, the wash medium entering through line 56 and discharging through line 81.

It .may also be desirable to recycle a part of the alkylationproduct and gases to aid- =in forming the emulsion which lmay be accomplished .by valved .line 58 which joins line 49. tion product is withdrawn through lineV 89, and sent to storage, or can be directed to blending tank I2 through line 89a. l

The alkylation of the isobutane with propylene in reactor 48 may also be -accomplished by using an aluminum chloride-parailln complex as a catalyst. This operation is carried out in a manner very similar to that employed when using sulfuric acid as a catalyst, the temperature of the reaction being maintained at 'about 15- to150 F. and preferably about '10 to 80 F.and 50 to 150 pounds per square inch pressure and preferably 75 pounds per square inchpressure gauge. n In those reactions where a low temperature is desirable heater 50 will naturally be a cooling means. Other catalysts which promote the allwlation of paraiiins with olehns are also contemplated in our invention.

'In fractionator 6| the washed alkylated product and unreacted gases are fractionated to yield a product* comprised essentially of branched- 'Y 'chain heptanes which, because of its saturated nature and high octane number, is suitable for use as a motor fuel in hi'ghfcompression engines. This is discharged from fractionator 8| through line 89 and 'sent to storage, or directed to" tank Il! for blending through line 88a. The unreacted C: and C4 carbon atoms are separated, the

The hydrocarbon-acid emulsion is With-- etc. In addition, it is possible to alkylate the antiknock value.

mixing means 19 and cooling jacket 80 are procycled to the alkylation reactor 48 through valved line 14 which joins Yline 49 or a part vmay be recycled and a part further alkylated by ethylene from fractionator 2| or preferably all of it may be alkylatedby ethylene. The butane which will contain normal butanes, the unreacted isobutane and-any remaining unreacted isobutylene or normal butylene is directed to alkylation reactor 15 -through valved line 16. The ethaneethylene fraction from fractionator 2| is led.

through line 11 to join line 16 and the mixture forced into alkylation reactor 15 by means of pump 18. The remaining isobutane'is allwlated by the ethylene present in the ethane-ethylene mixture using as'catalysts many of those mentioned as suitable for use in alkylation reactor ,48, namely, double salts, AlCls-parafn complex,

isobutane with ethylene using phosphorus pentoxide operating at about 525 F. and employing` a pressure of from 200 to about 800 pounds per square inch gauge. The primary product of this alkylation reaction will be branched-chain parafn hydrocarbons of 6 or 8 carbon atoms of high As in the case of reactor 48 vided to aid in carrying out the reaction under The alkylathe best conditions of contact and temperature. Catalyst may be injected by means of line 8|. The hydrocarbon-catalyst mixture' is withdrawn from alkylator 15 through a line 82 and separated in separator 83, the catalystbeing withdrawn through line 84 and discharged from the system through valved line 85 or recycledfor further use throughline 86 which joins line 8|. The separated hydrocarbons which will include the alkylated product and the unreacted gases pass overhead from separator 83 and while apart may be recycled to the alkylator by means of line 81, a larger portion is led to washer '88 by means of line 89 and directed to fractionator 90 through line 9|. ,'Wash medium may enter washer 88 through line 92 and discharge through line 98. From fractionator 90 having bottomheating means 94 and top cooling means 95 the` alkylation product comprising essentially branchedchain hexanes is withdrawn through line 96 for storage, or. sent through line 96a to'blendlng tank H2. The gases are separated into two fractions, one predominating in 4 carbon atoms and one predominately ethane land ethylene. The butane -is withdrawn from fractionator 90 by line 91 and maybe' recycled to the alkylation reactor 15 by valved line 98 which joins line 16 or to alkylation reactor 48 through line '99 which" joins line 49.

for blending with commercial gasolines .to incrse the volatility, utilized as fuel. dehydrogenated or' cracked to yield oleilnic hydrocarbons,

isomerized to yield i'sobutanes, etc. Generally speaking, the two-step alkylationprocess will remove the-isc-parafiins from the "butane cut so fraction is taken overhead from fra'ctionatorl 96 through line Il and may be recycled to alkylation reactor 15 through valved line |02 which joins line 11 or may be discharged *from the system through valvedline |031 for use as fuel.

Although we have thus far described our invention as directing the 3 carbon atoms cut to one alkylation reactor and the 2 carbon atom cut to another alkylation reactor it is possible to uti-` lize a mixture of the two in either orboth alkylation reactions. If it is desired to send both the 2 carbon and 3 carbon atom fractions to alkylator 48 this may be done through line -||ll which leads from line 11 to line 41. The ethylenecontaining fraction and the propylene-containing fraction may be directed to alkylator 15 by means of line |05 which leads from line 41 to line 11. It is also possible to direct the ethylene-containing fraction to allqlator I8' and the propylene-containing fraction to alkylator by a proper adjustment of the valves in lines 11, |04, 41 and |05. If it is desired, for example, to send ethylene `to alkylator 48 and propylene to alkylator 15 valve |05 will be closed, valve |01 opened, valve |08 closed, and valve I09 opened. It may also be desirable to increase the olen content of the gases for alkylation in which event extraneous ethylene or mixtures containl ing it may be introducedthrough line H0 while propylene-containing gases may be introduced through line ill.

The various reaction products from lines 42, 69

and 96 can be blended in tank |I2 to yield a highoctane number product of fairly wide boiling range, or they may be blended individually or in combination with ordinary gasoline to increase the octane number, with or without the addition of such agents as tetraethyl lead.

While we have described and illustrated certain specific embodiments of our invention, it is to be understood that these are not. by way of. limitation, and that various modifications and ramiiications will occur to those skilled in the We claim: 1. A process for the production of a motor fuel from a'mixture of normally gaseous hydrocarcontacting said fraction rich in isobutane, isobutylene and normal butylenes with a catalyst under conditions` adapted to polymerizea substantialportion of the oleiins insaid fraction, separating said polymerlaed oleilns from unreacted isobutane, contacting said separated isobutane with saidfiraction rich in at let one oleiinhaving ls than four carbon atoms per .molecule under adapted to promote the alkylaonotfat'leasta substantial portion of said isobutane with vsaid oleiin, and separating said aikylated isoinstnie fromunreacted hy- I2. A process for the production of -a motor fuel from a mixture of gaseous hydrocarbons containing substantial amoimts of isobutane, isobutylene, normal bublenes, propylene and ethylene which commises separating said mixture into a Al'ractioxi rich in said isobutane. iso- 2,340,600 thatrecycleisimnecessary. Theethane-ethylene butylene and normal butylenes, a second fraction rich in said propylene, and a third fraction rich in said ethylene, contacting said fraction rich in isobutane, isobutylene and normal butylenes with a catalyst under conditions adapted to promote the polymerization of a substantial part of the olens in said fraction, separating said polymerized olens from unreacted hydrocar- .bons including said isobutane, contacting said separated isobutane with at least one of the re- :maining fractions under conditions adapted to promote the alkylation of at least a, part of said separated isobutane with the olefin in said fraction, and separating alkylated isobutane from unreacted hydrocarbons.

3. A process for the production of a motor fuel from a mixture of normally gaseous hydrocarcions containing substantial amounts of isobutane, isobutylene, normal butylenes, propylene and ethylene which comprises separating said mixture into a. fraction rich in said isobutane, isobutylene and normal butylenes, a fraction rich in propylene and a fraction rich in ethylene, contacting said fraction rich in isobutane, isobutylene and normal butylenes with a catalyst under conditions adapted to promote the polymerization of at least a substantial portion of the oleilns in said fraction, separating said polymerized oleiins from unreacted gases including said isobutane, contacting said separated isobutane with one of the remaining fractions in the presence of a catalyst under conditions adapted to promote the alkylation of a least a part of said separated isobutane with the oleiln in said fraction, separating alkylated isobutane from unreacted hydrocarbons'including unreacted isobutane, contacting said unreacted isobutane with the other of the remaining vfractions in the presence of a catalyst under conditions adapted to promote the alkylation of at least a substantial part of said unreacted isobutane with the oleiin in said remaining fraction, and separating said last-mentioned alkylated isobutane from unreacted hydrocarbons. Y

' 4. A process for the production of a motor fuel from a mixture of normally gaseous hydrocai-, bons containing substantial amounts of isobutane, isobutylene, normal butylenes, propylene and ethylene which comprises separating said mixture into a `fraction rich in said isobutane, isobutylene and normal butylenes, a fraction rich in propylene and a fraction rich in ethylene, contacting said fraction rich in isibutane. isobutylene and normal butylenes with a catalyst under conditions adapted to promote the polymerization oi.A

at least-a substantial portion of the. oleiins in said fraction, separating said polymerized oleilns from unreacted gases including said isobutane. contacting said 'separated isobutane with said propylene-rich fraction in the presencey of a catalyst under-conditions adapted to promote th alkylation of at least a part of said isobutane with said propylene, separating alkylated isobutane from unreacted gases including unreacted isobutane, contacting said unreacted isobutane with said ethylene-rich fraction inl the presence oi' a catalyst under conditions adapted to promote the alkylaiton of at least a substantial part of said lmreacted isobutane with said ethylene, and separating said last-mentioned alkylated-isobutane from unreacted hydrocarbons.` v

- 5. A process for the production of a motor fuel from a mixture of normally gaseous hydrocarbons containing substantial amounts of isobutane, isobutylene, normal butylenes, propylene and ethylene which comprises" separating said' mixture into a fraction rich in said isobutane, isobutylene and normal butylenes, a fraction rich in propylene and a fraction rich in ethylene, contacting said fraction rich in isobutane, isobutylene and normal butylenes with a catalyst under conditions adapted to promoteA the polymerization of at least a substantial portion of the olens in said fraction,l separating said polymerized olens from unreacted gases including said isobutane, contacting said separated isobutane with one of the remaining fractions in the presence of a catalyst under conditions adapted to promote the alkylation of at least a part of said separated isobutane with the olen in said fraction, separating alkylated isobutane from unreacted hydrocarbons including unreacted isobutane, contactingsaid unreacted isobutane with the other of the remaining fractions in the presence of a catalyst under conditions adapted to promote the alkylation of at least a substantial part of said unreacted isobutane with the olen in said remaining fraction, separating said last-mentioned alkylated isobutane from unreacted hydrocarbons, and blending said alkylated isobutane from each of the alkylation steps with gasoline to form an improved motor fuel.

6. A process for the production of amotor fuel from a mixture of normally gaseous hydrocarbons containing substantial amounts of isobutane, isobutylene, normal butylenes, propylene and ethylene which comprises separating said mixture into a fraction Arich in said isobutane, isobutylene and normal butylenes, a fraction rich in propylene and a fraction rich in ethylene, contacting said fraction rich in isobutane, isobutylene and normal butylenes with a catalyst under conditions adapt- -ed to promote the polymerization of at least a substantial portion of the olefins in said fraction, separating said polymerized olens from unreacted gases includingsaid isobutane, hydrogenating said polymerized olens to form saturated parafnic hydrocarbons, contacting said separated isobutane with one of the remaining fractions in the presence of a catalyst under conditions adapted to promote the alkylation of at least a part of said separated isobutane with the olen in said fraction, separating alkylated isobutane from unisobutylene and normal butylenes with a .catalyst under conditions adapted to polymerize a substantial portion of the oleiins in said fraction, separating said polymerized olens from unreacted isobutane, contacting said separated lisobutane with said fraction rich in ethylene under conditions adapted to promote the alkylation of at 'least a substantial portion of said isobutane with said ethylene, and separating said alkylated isobutane from unreacted hydrocarbons.

8. A process for the manufacture of high antiknock motor fuel which comprises separating from hydrocarbon mixtures containing normally gaseous components a C: hydrocarbon fraction containing propylene and a C4 hydrocarbon fraction containing isobutane, isobutylene and normal butenes, contacting the C4 hydrocarbon fraction with a treating agent for removing isobutylene from the remaining C4 hydrocarbons including the isobutane and at least a part of the rnor` mal butenes, separately removing the remaining C4 hydrocarbons including isobutane an'd 'normal butenes from the treating agentl and products of the treating step, and subjecting said separately Y removed C4 hydrocarbons including isobutane and normal butenes together with the Ca hydrocarbon fraction containing propylene to the action of an alkylation catalyst under alkylation conditions in the presence of isoparafiins comprising isobutane whereby isobutane is alkylated by said propylene and normal butenes to produce high antiknock hydrocarbons within the gasoline boiling range.

9. The process of claim 8 wherein the treating agent is a polymerization catalyst and wherein the process includes the step of polymerizing removed isobutylene by means of said polymerization catalyst. Y

10. A process for the manufacture of high antiknock motor fuel which process comprises separating from hydrocarbon mixtures containing normally gaseous components a light hydrocarbon fraction rich in a mono-olefin of less than four carbon atoms and a C4 hydrocarbon fraction reacted hydrocarbons including unreacted isobutane, contacting said unreacted isobutane with the other of the remaining fractions in the presence of Aa catalyst under conditions adapted to promote the alkylation of at least a substantial part of said unreacted isobutane with the olefin in said remaining fraction, separating said lastmentioned alkylated isobutane from unreacted.

hydrocarbons, and,` blending said hydrogenated polymer and said alkylated isobutane from each of the alkylation steps to form an improved mop tor fuel.

'7. A process for the production of a motor fuel from. a mixture of normally gaseous hydrocarbons containing substantial amounts of isobutane, isobutylene. normal butylenes and ethylene which comprises separating said mixture into a fraction rich in said isobutane, isobutylene and normal butylenes and a fraction rich in saidethylene, contacting said fraction rich in isobutane,

containing isobutane, isobutylene and normal butenes, contacting the C4 hydrocarbon fraction with a treating agent for removing isobutylene from the'remaining C4 hydrocarbons including the isobutane and at least a part of the normal butenes, separately removingl the remaining C4- hydrocarbons including isobutane and normal butenes from the treating agent and products of the treating step, and subjecting the separately removed C4 hydrocarbons including isobutane and normal butenes together with the light hydrocarbon'fraction rich in the monoolen of less than four carbon atoms to the action of an alkylation catalyst under alkylation conditions whereby isobutane is, alkylated byy said monoolefin and normal butenes to produce high antiknock hydrocarbons within the gasoline boiling range.

ll. The process of claim 10 whereinf' the alkylation catalyst is an aluminum halidehydrocarbon complex-and wherein the light hydrocarbon fraction contains ethylene. p

GEORGE G. LAMB;

FORD H. BLUNCK. 

